Available Answers

1. 1.

   Fill in the blanks.

   1. Friction acts _______________ to the motion of an object.
   2. Oil and grease _______________ friction and are called _______________.
   3. Friction causes _______________ of energy.
   4. Rollers help in making the work easy because _______________ friction is less than the _______________friction.
   5. _______________ in the tyres helps the vehicle to move without skidding.
2. 2.

   Tick (√) the correct option.

   1. Talcum powder is used on the carrom board
      1. to increase friction
      2. to reduce friction
      3. to make surface shine
      4. to make the surface tough
   2. It is difficult to walk on ice because
      1. it is too cold
      2. friction is less
      3. friction is more
      4. surface is wet
   3. Friction produces a lot of
      1. light
      2. heat
      3. both light and heat
      4. none of these
   4. Fluid friction is due to
      1. only air
      2. only water
      3. only fluids
      4. all the above
3. 3.

   Match the columns.

   COLUMN A	COLUMN B
   1. Grooved shoe sole	a. Opposes the movement
   2. Ball bearing	b. Streamlined structure reduces friction
   3. Oil and grease	c. Walking
   4. Aeroplane and ships	d. Change sliding friction to rolling friction
   5. Friction	e. Lubricants

    

4. 4.

   Write one word for the following.

   1. The force that opposes the movement
   2. This converts sliding friction to rolling friction
   3. A substance used to reduce friction
   4. Force of friction due to air and water
5. 5.

   What is friction?

6. 6.

   State two advantages of friction.